International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-9 Issue-11, September 2020 119 Published By: Blue Eyes Intelligence Engineering and Sciences Publication Retrieval Number: 100.1/ijitee.K77110991120 DOI: 10.35940/ijitee.K7711.0991120 Abstract: In recent years, Guwahati city is witnessing a rapid urban growth due to ever-increasing human population sacrificing existing green pockets. This constant increase of built form is resulting in environmental imbalances and microclimate changes, contributing in a rise of indoor air temperature and that ultimately results a gradual increase in the energy consumption to maintain indoor thermal comfort in the inner-city areas. Although the urban growth pattern of Guwahati is controlled by prevailing GMDA building bye-laws, these building parameters are unable to control the organic growth of the city since there is no climate-sensitive approach available in the GMDA bye-laws. This paper aims to discuss the energy use in the building envelope by analysing the energy efficiency of a residential apartment building of Guwahati and reviews most common energy efficient codes that influences the heat gain or loss, natural ventilation, and day lighting, which, in turn, determines indoor temperatures, thermal comfort, and sensible cooling or heating demand inside urban residential buildings. Four relationships of building parameters are studied and analysed their impact on energy use. The amount of heat gain or loss, natural ventilation and day lighting that are allowed by building envelop will be calculated for each relationships and compared. All the relationships specify building envelope design that helps to improve the energy efficiency in residential building, but none suggested a basis for its proportion. This paper analyses the use of daylight and natural ventilation within a building envelope helps to minimise the energy consumption. A climate conscious urban design approach associating common energy codes such as window to floor area (WFR) ratio, Visual light transmittance (VLT) and residential envelope transmittance value (RETV) against average daylight and natural ventilation can be utilised as preliminary urban design techniques in development control regulations especially in the residential zones in the inner-city areas of Guwahati metropolitan development authority (GMDA). Keywords : Building envelope, energy efficiency, WFR ratio, RETV I. INTRODUCTION In recent years, sustainable development is the most crucial challenge we face in the urban scenario. Rapid and extensive urbanisation is leading to an uncontrolled urban heat island (UHI) effecting indoor and outdoor thermal comfort conditions in inner-city areas. High energy Revised Manuscript Received on September 05, 2020. * Correspondence Author Amal Barman*, Department of Architecture, Jadavpur University, Kolkata, India. E-mail: am_barman@hotmail.com Dr. Madhumita Roy, Department of Architecture, Jadavpur University, Kolkata, India. E-mail: mroy@arch.jdvu.ac.in Dr. Arpan Dasgupta, Amity school of Architecture and Planning, Amity University, Kolkata, India. E-mail: adgupta@kol.amity.edu consuming and environmentally detrimental buildings are no longer being considered as sustainable. To achieve gradual improvements that are necessary in building performance, there should be a better association among all involved in buildings – the users, builders, governments, NGO’s, teachers, architects and urban designers. Passive and low energy consuming climate responsive design significantly reduces the economic and environment costs of buildings. A climate responsive sustainable design is important at every level of human life. The energy consumption in residential sector is very high in India which is 22% and it is growing by 8% every year which is alarmingly high. To establish a minimum standard for energy efficient building design and construction of building, the energy conservation building codes (ECBC) are introduced by Bureau of energy efficiency (BEE). These energy efficient codes for buildings are important regulatory measures for calculating energy efficiency in the building. These energy codes regulates a minimum standard of energy efficiency in building envelope in different climatic zones of India and sets up five correlations between parameters of building envelope and daylight or ventilation factor. The building envelope consists of walls, roof, and fenestration (openings including windows, doors, vents, etc.). Design proposal of building envelope influences heat gain or loss, natural ventilation, and day lighting which determines indoor temperatures, thermal comfort, and sensible cooling or heating demand. The building envelope has the highest impact on thermal comfort, and consequently on the energy use in residential buildings. It is also the permanent component of the building with the longest life cycle. An early and efficient introduction of this code in the GMDA building bye-laws will improve the sustainable design and development of new residential building stock of Guwahati in the near future. Introduction of these codes will appreciably reduce the anticipated energy demand for comfort cooling especially in the residential building sector in times to come. This decisive speculation in building envelope design and construction will harvest the benefits of reduced green house gas (GHG) emissions for the lifetime of the buildings. This study initiates to study and analyse the energy use of a residential housing complex in Guwahati using energy codes to check the code of energy efficiency compliances of the dwelling units of the residential neighbourhood. Energy use in Building Envelope of a Residential Apartment Building in the Warm and Humid Climate of Guwahati, Assam Amal Barman, Madhumita Roy, Arpan Dasgupta